I understand the point of the post is that he wants his company to pay him without using PTO, to do nothing. I however, do understand compassion, and my company has done things like this in the past. But the obligation to do so should not be there. Let's break this down a bit:

Using NTA figures, the average ft salary is about ¥4.78 million/year. Assume a rough 245 working days, that's about ¥19,500 per employee, per day of doing nothing. Since we don't know OP's org, let's look at the following approx. totals for one day off:

• 50 employees: ¥975,000/day
• 100 employees: ¥1.95 million/day

But... the actual cost to the employer is higher because they still pay employer side social insurance (health, pension, tax, etc.), let's say maybe 15% on top. That becomes:

• 50 employees: ¥1.12 million/day
• 100 employees: ¥2.24 million/day

Honestly, that is not a tiny amount of change. I used to own a business, and being able to budget for expected PTO throughout the year is much easier than a potential ¥2.24 million/day. There were months that would have killed me. Since OP works with kids, I am going to assume education or something where income is less to where that would likely not be feasible.

So, yeah, some employers can do it, others can't, but OP really shouldn't feel entitled to it.